A light emitting diode (LED), particularly a blue or ultraviolet (UV) LED having an emission wavelength of approximately 250 to 550 nm, is a high-brightness product using a GaN-based compound semiconductor such as GaN, GaAlN, InGaN or InAlGaN. In addition, it is possible to form a high-quality full-color image by a method of combining red and green LEDs with a blue LED. For example, a technique of manufacturing a white LED in combination of a blue or UV LED with a phosphor has been known. Such LEDs are being widely used as backlights for liquid crystal displays (LCDs) or general lighting.
As an LED encapsulant, an epoxy resin having a high adhesive property and excellent mechanical durability is being widely used. However, the epoxy resin has a lower light transmittance of a blue light or UV ray region, and low light resistance. Accordingly, for example, the patent documents 1 to 3 disclose techniques for solving the above-described problems. However, encapsulants disclosed in the above references do not have sufficient thermal resistance and light resistance.
As a material having excellent light and thermal resistances with respect to a low wavelength region, a silicon resin has been known. However, the silicon resin has stickiness on a cured surface. In addition, to effectively apply the silicon resin as an encapsulant for an LED, characteristics such as high refractivity, crack resistance, surface hardness, adhesive strength and thermal and shock resistance need to be ensured.